Implications of structural differences between Cu-BTC and Fe-BTC on their hydrogen storage capacity

Hierarchical Porous Bimetallic FeMn Metal-Organic Framework Gel for Efficient Activation of Peracetic Acid in Antibiotic Degradation

Effective techniques for eliminating antibiotics from water environments are in high demand. The peracetic acid (PAA)-based advanced oxidation process has recently drawn increasing attention for its effective antibiotic degrading capability. However, current applications of PAA-based techniques are limited and tend to have unsatisfactory performance. An additional catalyst for PAA activation could provide a promising solution to improve the performance of PAA. Bulky metal-organic framework gels (MOGs) stand out as ideal catalysts for PAA activation owing to their multiple advantages, including large surface areas, high porosity, and hierarchical pore systems. Herein, a bimetallic hierarchical porous structure, i.e., FeMn13BTC, was synthesized through a facile one-pot synthesis method and employed for PAA activation in ofloxacin (OFX) degradation. The optimized FeMn MOG/PAA system exhibited efficient catalytic performance, characterized by 81.85% OFX degradation achieved within 1 h owing to the specific hierarchical structure and synergistic effect between Fe and Mn ions, which greatly exceeded the performance of the only PAA-catalyzed system. Furthermore, the FeMn MOG/PAA system maintained >80% OFX degradation in natural water. Quenching experiments, electron spin resonance spectra, and model molecular degradation revealed that the primary reactive oxygen species responsible for the catalytic effect was R-O•, especially CH3C(=O)OO•, with minor contributions of •OH and 1O2. Overall, introduction of the MOG catalyst strategy for PAA activation achieved high antibiotic degradation performance, establishing a paradigm for the design of heterogeneous hierarchical systems to broaden the scope of catalyzed water treatment applications.

Construction of n-type homogeneous to improve interfacial carrier transfer for enhanced photoelectrocatalytic hydrolysis

Photoelectrocatalyzed hydrogen production plays an important role in the path to carbon neutrality. The construction of heterojunctions provides an ideal example of an oxygen precipitation reaction. In this work, the performance of the n-n type heterojunction CeBTC@FeBTC/NIF in the photoelectronically coupled catalytic oxygen evolution reaction (OER) reaction is presented. The efficient transfer of carriers between components enhances the catalytic activity. Besides, the construction of heterojunctions optimizes the energy level structure and increases the absorption of light, and the microstructure forms holes with a blackbody effect that also enhances light absorption. Consequently, CeBTC@FeBTC/NIF has excellent photoelectric coupling catalytic properties and requires an overpotential of only 300 mV to drive a current density of 100 mA cm-2 under illumination. More importantly, the n-n heterojunction was found to be effective in enhancing charge and photogenerated electron migration by examining the carrier density of each component and carrier diffusion at the interface.

Boosting Electrochemical CO2 Reduction on Copper-Based Metal-Organic Frameworks via Valence and Coordination Environment Modulation

Cu-based metal-organic frameworks (MOFs) have attracted much attention for electrocatalytic CO2 reduction to high value-added chemicals, but they still suffer from low selectivity and instability. Here, an associative design strategy for the valence and coordination environment of the metal node in Cu-based MOFs is employed to regulate the CO2 electroreduction to ethylene. A novel "reduction-cleavage-recrystallization" method is developed to modulate the Cu(II)-Trimesic acid (BTC) framework to form a Cu(I)-BTC structure enriched with free carboxyl groups in the secondary coordination environment (SCE). In contrast to Cu(II)-BTC, the Cu(I)-BTC shows higher catalytic activity and better ethylene selectivity (≈2.2-fold) for CO2 electroreduction, which is further enhanced by increasing the content of free carboxyl groups, resulting in ethylene Faraday efficiency of up to 57% and the durability of the catalyst could last for 38 h without performance decline. It indicates that the synergistic effect between Cu(I)-O coordinated structure and free carboxyl groups considerably enhances the dimerization of *CO intermediates and hinders the hydrogenation of *CO intermediates in these competitive pathways. This work unravels the strong dependence of CO2 electroreduction on the Cu valence state and coordination environment in MOFs and provides a platform for designing highly selective electrocatalytic CO2 reduction catalysts.

Directed electron regulation promoted sandwich-like CoO@FeBTC/NF with p-n heterojunctions by gel electrodeposition for oxygen evolution reaction

Metal organic framework (MOF) is currently-one of the key catalysts for oxygen evolution reaction (OER), but its catalytic performance is severely limited by electronic configuration. In this study, cobalt oxide (CoO) on nickel foam (NF) was first prepared, which then wrapped it with FeBTC synthesized by ligating isophthalic acid (BTC) with iron ions by electrodeposition to obtain CoO@FeBTC/NF p-n heterojunction structure. The catalyst requires only 255 mV overpotential to reach a current density of 100 mA cm^-2, and can maintain 100 h long time stability at 500 mA cm^-2 high current density. The catalytic properties are mainly related to the strong induced modulation of electrons in FeBTC by holes in the p-type CoO, which results in stronger bonding and faster electron transfer between FeBTC and hydroxide. At the same time, the uncoordinated BTC at the solid-liquid interface ionizes acidic radicals which form hydrogen bonds with the hydroxyl radicals in solution, capturing them onto the catalyst surface for the catalytic reaction. In addition, CoO@FeBTC/NF also has strong application prospects in alkaline electrolyzers, which only needs 1.78 V to reach a current density of 1 A cm^-2, and it can maintain long-term stability for 12 h at this current. This study provides a new convenient and efficient approach for the control design of the electronic structure of MOF, leading to a more efficient electrocatalytic process.

Photo-induced reversible nitric oxide capture by Fe-M(CO2H)4 (M = Co, Ni, Cu) as a building block of mixed-metal BTC-based MOFs

Metal-organic frameworks incorporating mixed-metal sites (MM-MOFs) have emerged as promising candidates in the development of sensing platforms for the detection of paramagnetic species. In this context, the present study explores the photo-induced switching behavior of mixed-metal Fe-M (M = Co, Ni, Cu) formate (Fe-M(CO₂H)₄), as an experimentally feasible strategy for the reversible capture of nitric oxide (NO). Using Fe-M(CO₂H)₄ as a building block of synthesized MOFs based on BTC (benzene-1,3,5-tricarboxylic acid), molecular simulations of NO adsorption on Fe-M(CO₂H)₄ were conducted to provide a template for evaluating the behavior of BTC-based MOFs towards NO. Accordingly, the relationship between the magnetic properties and adsorption behaviors of Fe-M(CO₂H)₄ towards NO gas molecules was evaluated before and after photoexcitation. We show that the photo-induced effect on the magnetic properties of Fe-M(CO₂H)₄ changes the interaction strength between NO and the Fe-M(CO₂H)₄ systems. NO chemisorption over Fe-Ni(CO₂H)₄ indicates that nickel-doped Fe-BTC MOFs can be efficiently applied for capturing purposes. Moreover, our calculations show a switching behavior between physisorption and chemisorption of the NO molecules over Fe-Co(CO₂H)₄, occurring through magnetic modulation under UV-Vis irradiation. As far as we know, this is the first study that proposes light-controlled reversible NO capture using MOFs. The present study provides a promising platform for reversible NO capture using MM-MOF-incorporated BTC building blocks.

Parametric Study of Methyl Orange Removal Using Metal–Organic Frameworks Based on Factorial Experimental Design Analysis

Wastewater treatment plants (WWTPs) are one of the most energy-intensive industries. Every stage of wastewater treatment consumes energy, which is the primary contributor to WWTP costs. Adsorbents and process optimization are critical for energy savings. The removal of dyes from industrial wastewater by adsorption using commercially available adsorbents is inefficient. Metal–organic frameworks (MOFs) have outstanding properties that can improve separation performance over current commercial adsorbents, and thus, these materials represent a milestone in improving dye removal in water treatment methods. In this work, three types of metal–organic frameworks (Fe-BTC, Cu-BTC, and ZIF-8) have been investigated as prospective adsorbents for methyl orange removal from water in batch setups. The results showed that at 15 mg/L MO initial concentration and 100 mg dosage, Fe-BTC had the highest removal efficiency of 91%, followed by ZIF-8 (63%), and finally Cu-BTC (35%), which exhibited structural damage due to its instability in water. Fe-BTC maintained consistent adsorption capacity over a wide range of pH values. Furthermore, a 23 full factorial design analysis was implemented to evaluate the conditions for maximum MO-removal efficiency. The main effects, interaction effects, analysis of variance (ANOVA), and the Pareto chart were reported. The statistical analysis demonstrated that the MOF type was the most significant factor, followed by dosage and initial concentration. The analysis indicated that the type of MOF and dosage had a positive effect on the removal efficiency, while the initial concentration had a negative effect. The two-way and three-way interactions were also found to be significant.

Hybrid liposome/metal-organic framework as a promising dual-responsive nanocarriers for anticancer drug delivery

In this work, liposome-coated iron (III) benzene-1,3,5-tricarboxylate (Fe-BTC) metal-organic framework is examined as a promising pH/Ultrasound dual-responsive nanocarriers for doxorubicin (DOX) delivery. The successful coating of the MOF particles (Lip-Fe-BTC) with the phospholipid bilayer (PBL) was established by direct fusion into the synthesized liposomes. The liposome coating was verified using several techniques, including dynamic light scattering (DLS) and transmission electron microscopy (TEM). The DLS measurements showed an increase in the average particle diameter of liposomes from 150 nm to 163.1 nm for Lip-Fe-BTC particles. The Fe-BTC particles had the highest average particle diameter (287.3 nm). These results demonstrated that the PBL reduced the aggregation of the particles and improved their dispersity in the release medium. The TGA results demonstrated the MOF's excellent thermal stability. Furthermore, the nanocarrier's loading efficiency and capacity were determined to be ~90% and ~13.5 wt%, respectively. The in-vitro DOX release experiments demonstrated that the DOX-loaded Fe-BTC and liposome-coated Fe-BTC particles showed good pH and US dual-responsive capability, making them promising nanocarriers for drug delivery. The application of US enhanced DOX release from both Fe-BTC and liposome-coated Fe-BTC. In the case of Fe-BTC-DOX particles, the application of US enhanced the DOX release to around 38% and 67%, at pH levels of 7.4 and 5.3, respectively. Similarly, DOX release from the Lip-Fe-BTC-DOX particles reached ~35% and ~53%, at pH levels of 7.4 and 5.3, respectively. The MTT assay showed the biocompatibility and low cytotoxicity of these nanocarriers below 100 µg/ml.

A novel electrochemical sensor for glyphosate detection based on Ti3C2Tx/Cu-BTC nanocomposite

The copper benzene-1,3,5-tricarboxylate (Cu-BTC) with outstanding chemical and physical properties, is a novel and promising material in the field of electrochemical sensing. However, it has significant limitations for direct application in electrochemical sensing due to the relatively weak conductivity of Cu-BTC. Here, the conductivity of Cu-BTC was improved by loading Cu-BTC onto two-dimensional Ti₃C₂T_x nanosheets with high conductivity. Thanks to the synergistic effect produced by the high conductivity of Ti₃C₂T_x and the unique catalytic activity of Cu-BTC, the Ti₃C₂T_x/Cu-BTC nanocomposite exhibits excellent sensing performance for glyphosate, with a low limit of detection (LOD) of 2.6 × 10⁻¹⁴ M and wider linear sensing range of 1.0 × 10⁻¹³ to 1.0 × 10⁻⁶ M. Moreover, the electrochemical sensor based on Ti₃C₂T_x/Cu-BTC also shows excellent selectivity, good reproducibility and stability.

The Ti₃C₂T_x/Cu-BTC nanocomposite exhibits excellent sensing performance for glyphosate with a low detection limit and wide detection range. Moreover, the electrochemical sensor also shows excellent selectivity, good reproducibility and stability.

Ultrasonic-Assisted Synthesis of Fe-BTC-PEG Metal-Organic Complex: An Effective and Safety Nanocarrier for Anticancer Drug Delivery

The porous metal-organic complexes are emerging as novel carriers for effective and safe delivery of drugs for cancer treatment, minimizing the side effect of drug overuse during cancer treatment. This study fabricated the Fe-BTC-PEG metal-organic complex from Fe ions, trimesic acid, and poly(ethylene glycol) as precursors using an ultrasonic-assisted method. The morphology and crystallinity of the resultant complex were observed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. FTIR spectroscopy was employed to investigate the functional groups on the surface of the Fe-BTC-PEG complex. The result showed that the prepared Fe-BTC-PEG complex was in particle form with low crystallinity and diameter ranging from 100 to 200 nm. The obtained Fe-BTC-PEG complex exhibited a high loading capacity for the 5-fluorouracil (5-FU) anticancer drug with a maximal capacity of 364 mg/g. The releasing behavior of 5-fluorouracil from the 5-FU-loaded Fe-BTC-PEG complex was studied. Notably, the acute oral toxicity of the Fe-BTC-PEG metal-organic complex was also carried out to evaluate the safety of the material in practical application.

Photothermal-boosted effect of binary CuFe bimetallic magnetic MOF heterojunction for high-performance photo-Fenton degradation of organic pollutants

Overcoming the relatively low catalytic activity and strict acid pH condition of common photo-Fenton reaction is the key to alleviate the serious global burden caused by common organic pollutants. Herein, a binary homologous bimetallic heterojunction of magnetic CuFe₂O₄@MIL-100(Fe, Cu) metal-organic frameworks (MCuFe MOF) with photothermal-boosted photo-Fenton activity is constructed as an ideal practical photo-Fenton catalyst for the degradation of organic pollutants. Through an in-situ derivation strategy, the formed homologous bimetallic heterojunction with binary redox couples can simultaneously improve the visible light harvesting capacity and expedite the separation and transfer of photogenerated electrons/holes pairs, leading to the continuous and rapid circulation of both Fe^III/Fe^II and Cu^II/Cu^I redox couples. Notably, the heterojunction shows intrinsic photo-thermal conversion effect, which is found to be beneficial to boost the photo-Fenton activity. Impressively, MCuFe MOF shows remarkable catalytic performance towards the degradation of various organic pollutants by comprehensively increasing H₂O₂ decomposition efficiency and decreasing the required dosage of MCuFe MOF (0.05 g L^-1) with a wide pH range (3.0-10.0). As such, a photo-Fenton catalyst consisting of binary homologous bimetallic heterojunction is first disclosed, as well as its photothermal-enhanced effect, which is expected to drive great advance in the degradation of organic pollutants for practical applications.

Controllable Synthesis of 1, 3, 5-tris (1H-benzo[d]imidazole-2-yl) Benzene-Based MOFs

The growing interest in metal–organic frameworks (MOFs) in both industrial and scientific circles has increased in the last twenty years, owing to their crystallinity, structural versatility, and controlled porosity. In this study, we present three novel MOFs obtained from the 1, 3, 5-tris (1H-benzo[d]imidazole-2-yl) benzene (TIBM) organic linker. The formed TIBM crystal powders were characterized by scanning electron microscopy (SEM) to estimate the morphology of the particles, powder X-ray diffraction (XRD) to confirm the crystal structure, Brunauer–Emmett–Teller (BET) method for structural analysis, and thermogravimetric measurements to examine the thermal stability. The TIBM-Cu MOF showed excellent CO2 (3.60 mmol/g) adsorption capacity at 1 bar and 298 K, because of the open Cu site, compared to TIBM-Cr (1.6 mmol/g) and TIBM-Al (2.1 mmol/g). Additionally, due to the high porosity (0.3–1.5 nm), TIBM-Cu MOF showed a considerable CO2/N2 selectivity (53) compared to TIBM-Al (35) and TIBM-Cr (10).

Influence of various Cu/Fe ratios on the surface properties of green synthesized Cu-Fe-BTC and it`s relation to methylene blue adsorption

The incorporation of different percentages of Fe²⁺ into copper benzene-1,3,5-tricarboxylate (CuBTC) was successfully carried out at room-temperature synthesis with water as the only solvent. The XRD and XPS analysis shows that the Fe²⁺ were substituted into the paddlewheel structure. The incorporation of 18% Fe²⁺ into CuBTC can increase the surface area and porosity of the framework. The BET surface area of Cu₈₂Fe₁₈BTC (1240 m²/g) was significantly higher than CuBTC (708 m²/g). Further increase in the Fe²⁺ percentage will reduce the surface area of the compound. The presence of Fe²⁺ in the framework successfully disturbs the pore formation and widens the pore size on the surface of these compounds. This as well as the pH_pzc, which is related to the surface acidity of the resulting bimetallic organic framework (BMOF), play an important role in the adsorption process. Cu₅₃Fe₄₇BTC with an adsorption capacity of 94.42 mg/g shows approximately 6 times greater adsorption capacity against MB compared to CuBTC. This shows that by utilizing a different ratio of Cu and a second metal, it is possible to effectively design the surface morphology of BMOF for specific applications.

Passing the framework skeleton and properties of coordination materials onto organic framework materials

A practically applicable strategy for transforming fragile metal-organic frameworks (MOFs) into highly stable and ordered organic framework materials (OFMs) is developed by replacing the labile coordination bonds in MOFs with stable covalent bonds in OFMs, which exhibit hypothetically approximated topology, porosity and properties of the parent MOFs by merging the advantages of MOFs and porous organic materials, thus providing a general pathway for the synthesis of highly ordered OFMs with merged advantages of MOFs and organic polymers.

Enhanced stability and activity of Cu–BTC by trace Ru3+ substitution in water photolysis for hydrogen evolution

Constructing stable, efficient and cost-effective cocatalysts is of great significance for photocatalytic H2 evolution in a dye-sensitization system.

The Interaction of Hydrogen with Iron Benzene-1,3,5-Tricarboxylate (Fe-BTC)

Inelastic neutron scattering (INS) spectroscopy is used to explore the 0–12,000 cm−1 range to characterise the interaction of H2 with iron benzene-1,3,5-tricarboxylate (Fe-BTC). Two peaks are observed in the low energy (<350 cm−1) region after exposure to H2. Measurements with hydrogen deuteride (HD) confirm that the peaks originate from H2. The most likely explanation is that there are two populations of H2 (HD) present. For both the H2- and the HD-loaded samples, the higher energy peak is close in energy to that of the pure isotopomer, so it is assigned to bulk-like H2/HD held in pores of the Fe-BTC. The lower energy peak is assigned to H2/HD interacting directly with the Fe ion exposed on dehydration. It was also possible to detect the H–H stretch in the same experiment; however, unfortunately, the instrumental resolution is insufficient to separate the stretch modes of the bound H2 (HD) and that in the pores.

Enhanced visible light photocatalytic degradation of dyes in aqueous solution activated by HKUST-1: performance and mechanism

HKUST-1 is a copper-based metal–organic framework (MOF) and potential photocatalyst, but minimal research has addressed the performance and mechanism of HKUST-1 in the visible light photocatalytic degradation of dyes. In the present work, HKUST-1 was applied as a photocatalyst to activate peroxomonosulfate (PMS) under visible light (Vis) for dye removal in aqueous solution. The results showed that the removal efficiency of two cationic dyes [rhodamine B (RhB) and methylene blue (MB)] was greater than 95% within 120 min. Free radicals such as SO₄⁻˙, ·OH were present in the degradation process, with SO₄⁻˙ playing a dominant role. Zeta potential, X-ray photoelectron spectroscopy, and photoluminescence spectroscopy data were used to investigate the degradation mechanism. In the degradation process, surface charge attraction between HKUST-1 and cationic dyes promotes removal efficiency, with the degradation efficiency of cationic dyes (MB and RhB) more than 50% higher than for anionic dyes [acid orange 7 (AO₇) and methyl red (MR)]. On the other hand, HKUST-1 has been proved to activate PMS by conducting photoelectrons, which accelerated the degradation of dyes. Compared with the reaction conditions of PMS/Vis, when the HKUST-1 was present (HKUST-1/PMS/Vis), the degradation rates of MB and RhB increased by 62.7 and 63.2%, respectively.

HKUST-1 is a copper-based metal–organic framework (MOF). The HKUST-1/PMS/Vis system can effectively degrade RhB and MB but accomplish poor removal of AO₇ and MR, which is attributed to the repulsion between surface charges.

Fe-based metal–organic frameworks as heterogeneous catalysts for highly efficient degradation of wastewater in plasma/Fenton-like systems

Fe-based metal organic frameworks (Fe-MOFs) were successfully synthesized with the dielectric barrier discharge (DBD) plasma method and FeSO₄·7H₂O as the Fe precursor. Fe-MOFs were used as Fenton-like catalysts in DBD plasma/Fenton-like technology to treat wastewater, which addressed the issues with iron solubility. Since the valence state of iron will affect the catalytic performance, the Fe precursor FeSO₄·7H₂O was added to regulate the valence state and adjust the catalytic performance by improving the availability of active sites. The influences of discharge voltage, catalyst addition amount, H₂O₂ addition amount and pH on the degradation efficiency of methyl orange (MO) were systematically examined. Through free radical capture experiments, the reaction mechanism of the plasma/Fenton-like catalytic degradation process was deduced primarily as the coordinated oxidation process of hydroxyl radicals (·OH), photo-generated holes (h⁺) and superoxide radicals (·O₂⁻). The reusability experiments proved that the catalyst was stable and reusable. The possible degradation pathways were proposed based on the identification of intermediate products generated in the degradation process by liquid chromatography-mass spectrometry (LC-MS) analyses.

Fe-based metal organic frameworks (Fe-MOFs) were successfully synthesized with the dielectric barrier discharge (DBD) plasma method and FeSO₄·7H₂O as the Fe precursor.

The role of ultramicropores in the CO2 adsorption capacity of Fe–BTC crystallites synthesized with a perturbation-assisted nanofusion synthesis strategy

This study provides experimental proof of the remarkable effect of ultramicropores on the CO₂ adsorption capacity of Fe–BTC.

Removal of antimonite and antimonate from water using Fe-based metal-organic frameworks: The relationship between framework structure and adsorption performance

We investigated the adsorption performance of five Fe-based MOFs (Fe-BTC, MIL-100(Fe), MIL-101(Fe), MIL-53(Fe) and MIL-88C(Fe)) for removal of antimonite (Sb(III)) and antimonate (Sb(V)) from water. Among these MOFs, MIL-101(Fe) exhibited the best adsorption capacities for both Sb(III) and Sb(V) (151.8 and 472.8mg/g, respectively) which were higher than those of most adsorbents previously reported. The effect of steric hindrance was evident during Sb removal using the Fe-based MOFs, and the proper diameter of the smallest cage windows/channels should be considered an important parameter during the evaluation and selection of MOFs. Additionally, the adsorption capacities of MIL-101(Fe) for Sb(V) decreased with increasing initial pH values (from 3.0 to 8.0), while the opposite trend was observed for Sb(III). Chloride, nitrate and sulfate ions had a negligible influence on Sb(V) adsorption, while NO₃^- and SO₄^2- improved Sb(III) adsorption. This result implies that inner sphere complexes might form during both Sb(III) and Sb(V) adsorption.

A dual metal organic framework based on copper-iron clusters integrated sulphur doped graphene as a porous material for supercapacitor with remarkable performance characteristics

Herein, a novel bimetallic metal organic framework (MOF) using copper and iron as the metal centers with 1,3,5-tricarboxylic acid as a ligand (CuFeBTC) and its composite with sulphur doped graphene (S-GNS) have been investigated for supercapacitive performance. The synthesis of materials has been carried out using a facile wet chemical route. The physicochemical characterization of the materials employing various structural and surface techniques has been performed which confirms the successful formation of nanocomposite. The capacitive behavior of CuFeBTC, S-GNS and CuFeBTC/S-GNS has been systematically examined using 1 M Na₂SO₄ as an electrolyte in a three and two electrode assembly. The electrochemical studies reveal that CuFeBTC/S-GNS electrode demonstrates highest specific capacitance of 1164.3 F g^-1 at 0.5 A g^-1 with suffice rate capability as compared to CuFeBTC and S-GNS electrodes. Moreover, a symmetric supercapacitor is configured using the CuFeBTC/S-GNS nanocomposite electrodes which deliver remarkable energy and power output of 96.57 Wh kg^-1 and 1595.12 W kg^-1 at an operating voltage of 1.8 V. The as-fabricated symmetric supercapacitor displays competent energy storage retention of 50.2 Wh kg^-1 even at current density of 20.0 A g^-1 with high power density 26973.13 W kg^-1. These deliverables epitomize the latest performance record of bimetallic MOFs based supercapacitors, suggesting that CuFeBTC/S-GNS is a promising active material for high performance electrochemical energy storage applications.

Mixed-metal metal–organic frameworks

Mixed-metal MOFs contain at least 2 different metal ions presenting promising potential in heterogeneous catalysis, gas sorption/separation, luminescence and sensing.

Simultaneous laser-induced synthesis and micro-patterning of a metal organic framework

Micro-patterning of a metal organic framework (MOF) from a solution of precursors is achieved by local laser heating, alleviating the need for pre-preparation and stabilization.